U.S. patent application number 11/849287 was filed with the patent office on 2008-01-10 for method for inspection of metal tubular goods.
This patent application is currently assigned to TECHNICAL INDUSTRIES, INC.. Invention is credited to Jeffrey S. Banks, Dennis L. Rogers, George M. Sfeir.
Application Number | 20080006090 11/849287 |
Document ID | / |
Family ID | 32990702 |
Filed Date | 2008-01-10 |
United States Patent
Application |
20080006090 |
Kind Code |
A1 |
Sfeir; George M. ; et
al. |
January 10, 2008 |
Method for Inspection of Metal Tubular Goods
Abstract
A method for inspection of tubular goods includes using
ultrasonic detection means to obtain wall thickness measurement of
discrete sections of a tubular good and recording each measurement
in association with both the longitudinal and circumferential
position at which each measurement was obtained. Accordingly each
measurement of wall thickness represents a small portion of the
wall thickness of said tubular in three dimensional space. A
plurality of said measurements may thereby be displayed by computer
means in virtual three dimensional format. Differing wall thickness
readings made be represented by different shading or color display,
so that anomalies of interest may be readily detected.
Alternatively the recorded information may be readily processed by
computer means to calculate the effect of stressors on the wall of
said tubular good.
Inventors: |
Sfeir; George M.;
(Lafayette, LA) ; Banks; Jeffrey S.; (Crosby,
TX) ; Rogers; Dennis L.; (Houston, TX) |
Correspondence
Address: |
LEMOINE & ASSOCIATES L.L.C.
406 AUDUBON BLVD.
LAFAYETTE
LA
70503
US
|
Assignee: |
TECHNICAL INDUSTRIES, INC.
Lafayette
LA
70503
|
Family ID: |
32990702 |
Appl. No.: |
11/849287 |
Filed: |
September 1, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10548731 |
Sep 7, 2005 |
7263887 |
|
|
PCT/US04/07010 |
Mar 8, 2004 |
|
|
|
11849287 |
Sep 1, 2007 |
|
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|
60452907 |
Mar 7, 2003 |
|
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Current U.S.
Class: |
73/602 ;
73/622 |
Current CPC
Class: |
G01B 17/02 20130101;
G01N 29/07 20130101; G01N 2291/2634 20130101; G01N 29/0609
20130101; G01N 2291/02854 20130101; G01N 29/043 20130101; G01N
2291/0234 20130101 |
Class at
Publication: |
073/602 ;
073/622 |
International
Class: |
G01N 29/04 20060101
G01N029/04 |
Claims
1. Method for collection and storage of information representing
wall thickness of tubular goods, comprising: a. selecting a section
of the wall of a tubular good about which information representing
wall thickness is to be acquired and then stored in a format
readable by computer means; b. determining number and spacing of
discrete portions within said section of the wall of said tubular
good which will produce information representing wall thickness of
said section of the wall of said tubular good having desired
resolution; c. at each of said discrete portions, causing said
ultrasonic detection means to determine the thickness of the wall
of said tubular good; d. at each of said discrete portions,
determining the longitudinal position of said ultrasonic detection
means along the axis of said tubular good; e. at each of said
discrete portions, determining the circumferential position of said
ultrasonic detection means about the circumference of said tubular
good; and, f. at each of said discrete portions making a computer
readable recording of said wall thickness, longitudinal and
circumferential positions in an associated relationship.
2. The method of claim 1 wherein said number of said discrete
portions within said section of the wall of said tubular good is
greater than two for each circumference of said tubular good.
3. The method of claim 1 wherein said number of said discrete
portions within said section of the wall of said tubular good is
greater than sixty-four for each circumference of said tubular
good.
4. The method of claim 1 wherein said number of said discrete
portions within said section of the wall of said tubular good is at
least three hundred and sixty for each circumference of said
tubular good.
5. The method of claim 1 wherein said spacing of said discrete
portions within said section of the wall of said tubular good is
such that each determination of wall thickness partially overlaps
an adjacent discrete portion of said section of said wall of said
tubular good.
6. The method of claim 2 wherein said spacing of said discrete
portions within said section of the wall of said tubular good is
such that each determination of wall thickness partially overlaps
an adjacent discrete portion of said section of said wall of said
tubular good.
7. The method of claim 3 wherein said spacing of said discrete
portions within said section of the wall of said tubular good is
such that each determination of wall thickness partially overlaps
an adjacent discrete portion of said section of said wall of said
tubular good.
8. The method of claim 4 wherein said spacing of said discrete
portions within said section of the wall of said tubular good is
such that each determination of wall thickness partially overlaps
an adjacent discrete portion of said section of said wall of said
tubular good.
9. The method of claim 1 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to display wall of the tubular
good in virtual three-dimensional form.
10. The method of claim 2 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to display wall of the tubular
good in virtual three-dimensional form.
11. The method of claim 3 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to display wall of the tubular
good in virtual three-dimensional form.
12. The method of claim 4 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to display wall of the tubular
good in virtual three-dimensional form.
13. The method of claim 1 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
14. The method of claim 2 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
15. The method of claim 3 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
16. The method of claim 4 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
17. The method of claim 5 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
18. The method of claim 6 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
19. The method of claim 7 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
20. The method of claim 8 further comprising the step of causing a
computer means to use at least some of the information contained in
said computer readable recording to compute the effect of stressors
on the wall of said tubular good.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuing application of U.S. patent
application Ser. No. 10/548,731 filed Sep. 7, 2005 soon to issue as
U.S. Pat. No. 7,263,887 which emanates from International Patent
Application No. PCT/US04/07010 filed Mar. 8, 2004 which claims
priority to the Provisional Patent Application No. 60/452,907 filed
Mar. 7, 2003.
FIELD OF THE INVENTION
[0002] The invention disclosed herein relates to non-destructive
inspection of tubular metal goods. More particularly the invention
herein disclosed relates to a non-destructive means for
determination of wall conditions, in particular wall thickness
data, of tubular metal goods by use of ultrasonic detection
apparatus. With additional specificity the invention disclosed
herein relates to an improved method of collecting, storing,
displaying and otherwise utilizing information resulting from
ultrasonic detection of the wall of metal tubulars. With even more
specificity the invention herein disclosed relates to the use of
ultrasonic means to acquire incremental data representing small,
discrete sections of a tubular wall in association with
three-dimensional positional data pertaining to each small,
discrete section, so that the wall of a metal tubular (or portions
thereof) can be displayed, imaged, examined and utilized in
simulative/comparative programs as a three-dimensional object.
BACKGROUND OF THE INVENTION
[0003] In many applications inspection of metal tubular goods for
the presence of possible defects is highly desirable and/or
required. Inspection of metal tubulars is common in, for instance,
the oil and gas exploration and production industry, in refineries
and/or in chemical and other plants, where the failure of such
tubulars may result in serious consequences.
[0004] The art of inspecting metal tubulars for possible defects
has experienced various improvements over the course of time. Early
testing was rudimentary. It sometimes consisted of no more than
visual inspection of the exterior of the tubular for such defects
as might be seen. This method was obviously limited. Sometimes
inspection might include an attempt to "ring" or "sound" the
tubular. This generally involved striking the tubular with a hard
object, such as a hammer, and listening to the sound the tubular
produced. An abnormally "flat" tone may indicate that the tubular
was cracked. This method was highly subjective and even if employed
by skilled personnel was unable to detect small defects.
[0005] The need to improve inspection of metal tubulars led to
other developments, such as magnetic testing. One method of
magnetic testing involved magnetizing the tubular (or a portion
thereof), "dusting" same with ferromagnetic powder and then
visually inspecting for abnormal distribution of the powder. In
another method of magnetic testing an electromagnetic coil was
passed close to the surface of the tubular and various means used
to determine disturbance of the induced eddy current possibly being
caused by discontinuities in the tubular. Neither method was well
suited for detection of small defects and/or those below the
surface of the tubular, were time consuming, were largely dependent
on the skill of the operator and did not produce precise data from
which the effect of a condition found might be mathematically
calculated.
[0006] Another attempt to improve inspection of metal tubulars was
the dye penetrant method. In such method the tubular was cleaned,
coated with a penetrating fluid containing dye (typically of a type
which would fluoresce under certain lighting conditions), wiped and
then visually inspected for surface discontinuities still
containing dye. This method was not useful for detection of
sub-surface defects and did not produce precise data from which the
effect of a condition found might be mathematically calculated.
[0007] Another means to inspect metal tubulars is by utilization of
X-rays. While x-ray represents a way to determine some defects
below the surface of the tubular wall, certain defects such as thin
cracks and delaminations are difficult to find by X-ray. Moreover
this method of inspection does not produce precise data from which
the effect of a condition found might be mathematically calculated.
Because of the danger, shielding requirements, expense and
limitations of this technology, its use has been limited.
[0008] An attempt to inspect metal tubular goods for wall thickness
defects was represented by utilization of gamma radiation. In one
method the gamma source is placed on one side of the tubular and a
radiation sensor on the other side of the tubular. By measuring the
decrease in radiation as it passes through the tubular an
estimation of the collective wall thickness of both sides of the
tubular can be made. This method has certain disadvantages,
including but not necessarily limited to relative insensitivity of
the sensor to small thickness changes, its inability to detect if
one side of the tubular is thick and the other thin (which is not
an uncommon defect, particularly in extruded tubulars) and the
safety, security and administrative issues relating to utilization
of radioactive sources. Moreover such inspection does not produce
data from which the effect of a condition found might be calculated
with mathematical precision.
[0009] In attempt to avoid the limitations of the above technology,
ultrasonic technology was developed for inspection of tubular
goods. In general, this technology is based on the speed of sound
in metal and the fact that a sound wave will reflect ("echo") from
medium interfaces. Thus by propagating a sonic wave in said metal
and by measuring the time it takes for echos of that wave to return
from an interface, it is possible to determine the precise distance
to said interface. Such interface may, of course, be the opposite
wall of the tubular. Accordingly by use of ultrasonic means precise
wall thickness of a tubular at an area may be determined. In order
to determine the wall thickness of a tubular about the whole area
of the tubular, the tubular is typically rotated about its axis and
advanced longitudinally in relation to an ultrasonic head which
periodically "fires" and effectively samples wall thickness under
the head at the time. As the tubular advances a stream of data
points, each one representing a wall thickness measurement is
generated. Typically the data resulting from such testing is
displayed in two-dimensional form, as a numeric table or as a line
on a graph (representing wall thickness at a position on the length
of the tubular). Out-of-range values can be detected either by
human reading the table or graph, or by machine (computer)
detection of out of range values. From such data the general
location of a suspected defect along the length of tubular, its
magnitude and direction (whether too thin or too thick) can be
determined and the tubular joint marked for acceptance, rejection
or repair, but said data was not useful for substantial purposes
there beyond. Namely, without three-dimensional data as to both the
defect and the remainder of the tubular, the effect that defect
might have concerning performance of the tubular could not be
calculated with mathematical precision.
[0010] The invention disclosed herein relates to improved method to
acquire, collect, assemble, store, display and/or utilize data
stemming from ultrasonic inspection of tubular goods, not only for
a determination for the presence or absence of defects, but so that
data from the inspection may be used to calculate projected
performance of the tubular with a mathematical precision not
previously available by non-destructive evaluation of the
tubular.
OBJECTS OF THE INVENTION
[0011] The general object of the invention disclosed herein is to
provide an improved means for collection, assembly, storage,
display, analyze and other utilization of information derived from
ultrasonic inspection of tubular goods. A particular object of the
invention is associate data representing incremental ultrasonic
measurements of wall of discrete, small sections of a tubular with
three-dimensional positional information identifying each discrete
section of the tubular at which each wall measurement was obtained,
so that the data may be displayed, presented, analyzed and
otherwise used (either by visual means or mathematically) as a
three-dimensional object. Another object of the invention is to
collect, assemble and/or store wall thickness data of metal
tubulars in a form which is susceptible to display, presentation,
analysis or other use as a three-dimensional object, including but
not limited to display, presentation and analysis as a
three-dimensional image which my be viewed from any perspective,
zoomed, rotated, each data point individually examined, used in
mathematical calculations predicting performance of the tubular
under certain conditions, compared with previous or subsequent data
and thereby used to project future changes, used in engineering
calculations and/or programs which predict response of the tubular
to various stressors and otherwise have increased utility.
DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
[0012] While the present invention will be described with reference
to preferred embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, modifications may be made to adapt a
particular situation or material to the teachings of the invention
without departing from the essential scope thereof. It is therefore
intended that the present invention not be limited to the
particular embodiments disclosed herein, but that the invention
will include all embodiments (and legal equivalents thereof)
falling within the scope of the appended claims.
[0013] In order to practice the invention herein disclosed an
ultrasonic means is provided for measuring the wall of small areas
of a metal tubular. In preference this will be accomplished by
positioning an ultrasonic head in close proximity to the exterior
of the tubular and substantially perpendicular to both the
longitude and a tangent of the tubular. In preference said head
will include an ultrasonic transducer for propagating an ultrasonic
wave radially inward (towards the longitudinal axis of the tubular)
and for receiving ultrasonic reflections ("echos") returning from
the opposite direction. In preference said head will be coupled to
the tubular by a medium which effectively transmits ultrasonic
waves across the interface between the medium and the tubular, for
example by water coupling, or by other means well known in the
field of art.
[0014] As is well known, by accurately measuring the length of time
it takes for the ultrasonic wave to travel from the outer wall of
the tubular to the interior wall, reflect from the interior wall
and return to the outer wall (known as "time-of-flight" or "TOF"),
the distance ("D") the wave has traveled may be readily calculated
[from the formula D (distance)=S (speed).times.TOF, the speed of
sound in various metals being well known]. Wall thickness of the
tubular at the area so sampled is one-half of "D".
[0015] While those skilled in the art will realize that there are
many other practical considerations to obtaining accurate
measurement of the wall thickness of a tubular at a particular
location by ultrasonic means, including but not limited to, issues
relating to ultrasonically coupling the transducer and tubular,
issues relating to excluding the effects of coupling from the
calculations, issues relating to excluding subsequent reflections
from the surfaces, issues relating to accurately "starting" and
"stopping" timing measurements in a precise and consistent manner,
and, other such issues. As these considerations, and various
solutions, are well known to those skilled in the art, they will
not be further discussed herein. As it relates to the invention
disclosed, it is only necessary that some ultrasonic means be
provided to obtain incremental measurements of small, discrete
selectable sections of the tubular by ultrasonic means.
[0016] In order to practice the invention, a means must also be
provided to obtain incremental measurements of small, discrete wall
segments throughout the entire area of the tubular of interest
(which in most cases will be the entirety of the tubular). In the
preferred embodiment this is accomplished by rotating the tubular
about its longitudinal axis as the ultrasonic head advances
longitudinally along the length of the tubular, and periodically
triggering ("firing") the ultrasonic head to make a wall
measurement (a "snapshot") of the area of the tubular adjacent
thereto at the time. In preference the rate of rotation,
longitudinal advance, rate of triggering the ultrasonic head, and
size of the ultrasonic head will be such that each snapshot of the
wall partially overlaps, both circumferentially and longitudinally
with adjacent snapshots, so that complete coverage of the entire
area of the tubular to be inspected (which will in most cases be
the entire tubular) is obtained. In the preferred embodiment of the
invention this is accomplished by disposing the tubular
horizontally on a roller system where it may be rotated about its
longitudinal axis. In preference the ultrasonic head will be above
and adjacent to the upper surface of the horizontally tubular and
pointed so as to propagate waves perpendicularly downward toward
the tubular. In preference the tubular will be rotated at constant
speed, and as it is so rotated, the ultrasonic head advances
longitudinally at constant speed, so that the relative movement
between the head and the tubular substantially follows a spiral
path along the outer surface of the tubular. As the tubular is so
advanced the ultrasonic head is periodically fired to take a
snapshot of the wall of the tubular. Each of these snapshots is a
mathematical representation, a "number", which represents wall
thickness of the tubular under the ultrasonic head at the time it
is fired. Each of these snapshots will be recorded. Accordingly, at
the end of the process a plurality of incremental wall thickness
snapshots will have been recorded which represents at least
partially overlapping coverage of the entire area of the tubular to
be inspected (which will in most cases be the entirety of the
tubular).
[0017] It will be appreciated by those skilled in the art that a
similar result might be obtained by "sampling" (incrementally
obtaining data representing small, discrete sections of the wall of
a tubular) in a different manner or order. It will be appreciated
that the tubular could be disposed other than horizontally during
sampling or even disposed in varying positions during sampling. It
will be appreciated that sampling might be done by incremental
rotation and/or longitudinal advancement and stopping of the
tubular, rather than continuous rotation and longitudinal
advancement of the tubular (or ultrasonic head) during sampling. It
will be appreciated that sampling might be accomplished along a
plurality of longitudinal lines about different circumferences of
the tubular, or by a plurality of circular lines about different
longitudes of the tubular, rather than by sampling along a spiral
path. It will be appreciated that the ultrasonic head may be
rotated about the tubular rather than the reverse. It will be
appreciated that the tubular may be advanced longitudinally with
respect to the ultrasonic head rather than the reverse. It will be
appreciated that multiple ultrasonic heads may be used. It will be
appreciated that sampling may even be accomplished in a random
manner. All of these permutations are intended to be comprehended
by the invention disclosed herein, the thrust of which does not
relate to the particular order in which discrete snapshots of small
wall segments of the tubular are obtained and recorded for the
entirety of the area of the tubular to be inspected, but that such
result is obtained. Namely at the end of the sampling it is desired
to have obtained and recorded, with mathematical precision, a
plurality of snapshots of the wall of the tubular, each of which
represents a wall thickness of a small discrete section of the
tubular, in combination with all of the snapshots covering the
entire area of the tubular of interest.
[0018] In addition to recording discrete snapshots of small
sections of the tubular wall over the entire area of the tubular of
which is of interest (which in most cases will be the entire
tubular), in the invention disclosed herein positional information
will also be obtained and recorded as to the location on the
surface of the pipe at which each snapshot was taken. In addition
thereto, each particular snapshot will be associated with the
particular positional information unique to that snapshot.
[0019] In the preferred embodiment of the invention, the position
of each snapshot of the wall of the tubular is obtained by marking
the exterior of the tubular with a longitudinal line which is
detectable by photoelectric cell. This line forms a circumferential
reference which in the preferred embodiment is treated as a "zero
degree" reference. Those skilled in the art will know the reference
need not necessarily be considered a zero degree reference, but
could in fact be given any other mathematical value (all of which
are comprehended by the invention). Each time the tubular is
rotated the photoelectric cell is triggered by the reference line.
In the preferred embodiment of the invention, each time the cell is
triggered the stream of data (representing a stream of discrete
wall thickness measurements) is "marked" with an indication that
one rotation of the tubular has occurred. In the preferred
embodiment of the invention within each rotation each is assigned a
numerical value representing the order within that rotation which
that particular snapshot was taken (i.e., the first snapshot
following triggering of the photoelectric cell will be assigned a
value representing 1, the second snapshot assigned a value
representing 2, etc.). Those skilled in the art will recognize that
any mathematical value could be assigned so long as the assigned
value could be subsequently correlated to a circumferential
position at which each snapshot could be taken, therefore is
comprehended by the invention disclosed herein.
[0020] Within each rotation of the pipe the numerical value
representing the order in which each snapshot within that
revolution of the pipe may of course be converted to a value which
represents the angle, from the reference line, at which that
snapshot was taken or, in conjunction with knowing the position
along the longitude of the tubular at which that rotation occurred,
may be converted to some other form (for example, traditional "X,
Y, Z" coordinates) which represents the position on the tubular at
which each snapshot was taken.
[0021] In the preferred embodiment of the invention the data
representing one rotation of the pipe is longitudinally
synchronized with snapshots of another revolution of the tubular,
so that accurate alignment of data along a longitude is maintained,
even if speed of rotation of the tubular was not exactly the same
in one rotation as another rotation, or other conditions have
occurred where the number of snapshots in one revolution of the
tubular is not exactly the same as the number of snapshots in other
revolutions. In the preferred embodiment of the invention,
synchronizing the circumferential data once each revolution of the
tubular has been found adequate. In the preferred embodiment of the
invention, synchronization is accomplished by computer means which
converts the value which represents the order in a particular
revolution pertaining to each snapshot to a value which represents
angular position of each snapshot about the circumference of the
tubular. Thus, if in one revolution there were 400 data points
(each of which represented a wall thickness reading, or
"snapshot"), the 100th data point will be converted to a value
which will interpreted to be 90.degree. from the reference marking,
the 200th data point converted to a value representing 180.degree.
from the reference marking, etc. Whereas if in a different
revolution there are 500 data points, then the 125th data point
will be converted to a value which will be interpreted to be
90.degree. from the reference marking, the 250th data point
converted to a value representing 180.degree. from the reference
marking, etc. In this way all the data points in one rotation of
the tubular are longitudinally synchronized with all data points
corresponding longitudinally in other revolutions of the tubular.
It will be appreciated that synchronization of data could be
accomplished more frequently or less frequently than once each
revolution, or by means other than use of an external reference
line detectable by a photoelectric cell. It will be appreciated
that instead of converting position of the discrete snapshots about
the circumference of the tubular into angular format, said position
could be represented as a point in any coordinate system. For
purposes of the invention disclosed herein it does not matter how
the position about the circumference of the tubular that each of
the discrete snapshots of the wall thickness is mathematically
represented, but rather that such circumferential information about
each snapshot is obtained and recorded with mathematical
precision.
[0022] In the preferred embodiment of the invention not only will
circumferential position of each wall thickness measurement
("snapshot") be obtained, but longitudinal position of each
snapshot will also be obtained, recorded and associated, with
mathematical precision, to each discrete snapshot. In the preferred
embodiment of the invention it is the ultrasonic head which moves
along a line parallel to the axis of the tubular during inspection
thereof. In the preferred embodiment of the invention a sensor on
said head generates a signal as to its position along the longitude
of the tubular each time the transducer is fired. Thus in the
preferred embodiment this signal is recorded each time the head is
fired (to take a wall thickness reading, a "snapshot" of the wall).
Those skilled in the art will recognize that longitudinal position
of each snapshot might be obtained by other means, including but
not limited to measuring the relative speed of longitudinal
movement between the tubular and ultrasonic head as a function of
time, counting the number of revolutions it takes for a tubular to
advance a certain distance in respect to the head and thereby
calculating the point along the spiral path which each snapshot was
taken, or other means. For purposes of the invention disclosed
herein the particular manner of obtaining the longitudinal position
at which each wall thickness snapshot is taken is not important,
but rather that such data is obtained, recorded and associated with
each snapshot, with mathematical precision. Accordingly at the
conclusion of the process there will have been obtained and
recorded a plurality of overlapping measurements of small discrete
sections of the wall of the tubular. Each measurement will include
a mathematically precise representation of wall thickness and be
associated with a mathematically precise three-dimensional
representation the place on the tubular where that measurement of
the wall was obtained from. The plurality of such readings will
cover the entire area of the wall of interest, which in most case
may be the entire tubular.
[0023] It will however be appreciated that the invention is not so
limited. Namely the entire area of the tubular need not necessarily
be sampled. Rather by appropriately triggering the ultrasonic head
to fire only between certain areas of the rotation of the tubular
one might limit inspection to the longitudinal weld line of the
pipe. Alternatively the ultrasonic head may be adjusted to fire
only at certain longitudinal positions of the pipe, thus, for
instance limit inspection to certain areas along the length of the
pipe. Alternatively both might be the ultrasonic head may be set to
only within certain circumferential or longitudinal limits,
defining a relatively small section of the pipe to be inspected
according to the invention. Such permutations are fully
comprehended by the invention.
[0024] It will also be appreciated that sampling according to the
invention need not necessarily be of contiguous areas of the pipe,
or comprise overlapping snapshots. It is comprehended that the
invention may be utilized with spaces between snapshots. While
leaving spaces between snapshots may fail to reveal a small defect
in the space not sampled, the data gathered by the invention will
still form that of a virtual three-dimensional object which has
utility, for instance in simulative and modeling programs, far
above that currently available.
[0025] So far as synchronization of longitudinal data, such
synchronization has not been found necessary if the tubular is
rotated according to the preferred embodiment discussed above,
because while there are a plurality of rotations of the tubular
(which may require synchronization as discussed above), there is
only one longitudinal advancement of the tubular. Accordingly there
is no plurality of discrete sets of data, each representing a
discrete longitude of the tubular, to be synchronized with other
data also representing a longitude of the tubular. This would be
different if the data were gathered or recorded in a different
manner which resulted in different sets of data, each of which said
sets represented a longitude of the tubular. In this instance, it
would be desirable to convert the number of data points in each set
to correspond to the known length of the tubular, so that the
discrete sets of longitudinal data would correspond to that length
and therefore each other. Accordingly, comprehended by the
invention herein is circumferential and/or longitudinal
synchronization of data, as may be necessary.
[0026] In the preferred embodiment of the invention, effective size
of the transducer is about one-half inch in diameter. Accordingly,
in the preferred embodiment of the invention, to assure full
coverage of the area of interest in the preferred embodiment
described above, a rate of rotation and triggering of the
transducer is selected so that the transducer each triggered as the
tubular rotates about 3/8th inch (or less), and each rotation of
the tubular results in a longitudinal advancement of the tubular
about 3/8th inch (or less). It will be appreciated by those skilled
in the art that rate of rotation and advancement would vary if a
transducer of different size were used, the objective being to
assure snapshots which partially overlap. It will be appreciated
that the smaller the effective area of the ultrasonic head the
finer resolution of wall thickness will be obtained, but at the
sacrifice of speed and accumulation of larger amounts of data.
[0027] It may be appreciated that since in the preferred embodiment
of the invention each snapshot (representing measurement of wall
thickness of the tubular at a discrete location) at least partially
overlaps adjacent snapshots, at least where such overlap occurs
there may be two, possibly more, measurements of wall thickness. It
may be also appreciated that the measurements may not be exactly
the same, since each covers at least a portion of the surface that
the adjacent snapshot does not cover. It may be appreciated that
where such overlap occurs and is not identical, there is presented
an ambiguity as to the value to be assigned the wall thickness
where such overlap occurs. In the preferred embodiment of the
invention it is the value which represents the smallest
("thinnest") wall thickness which is assigned this area, because a
thin wall condition is believed to represent the greatest risk of
failure of the tubular. However, this does not have to be so. The
value which represents the thickest wall section could as easily be
used, or an average between the multiple reading could be assigned
to the area where such overlap occurs. All are comprehended by the
invention herein disclosed.
[0028] Accordingly, in the preferred embodiment of the invention,
partially overlapping wall thickness measurements representing
discrete, incremental, overlapping measurements of small areas of
the tubular as well as positional information of each discrete
measurement of wall thickness will be obtained and will be
associated with each other. In the preferred embodiment of the
invention the requisite association of each discrete measurement of
wall thickness with the positional information pertaining to that
measurement is accomplished by digital means. That is both
measurement of wall thickness and positional information are
converted to digital format appended together as one data point.
Those skilled in the art will recognize that other forms of
association, including but by not limited to use of cross-reference
table, would also work. For purpose of the invention the manner
that each discrete measurement of wall thickness is associated with
respective positional information is not of particular importance,
only that such association be made. It is however particularly
useful (while the invention is not limited thereby) that such data
be associated in a form that is readable by computer means, in
order to facilitate computer display, analysis and use of the
information.
[0029] Data contained in such format may be used in ways not
previously possible. For instance, the data representing wall
thickness may be, by computer means, shade and/or color coded and
presented in virtual three-dimensional form, which clearly
resembles visual inspection of the tubular, or sections of
particular interest, from almost any perspective, from any apparent
distance, with or without enlargement, as if the walls of the
tubular were color and/or shaded coded (different thicknesses
represented different colors and/or shades).
[0030] Moreover, the precise numerical value of the thickness of
any section and its precise location on the tubular, may be
obtained from such presentation. While the preferred embodiment of
the invention uses "Open GL" computer graphic rendering software to
display the tubular data, those skilled in the art will recognize
that other computer graphic rendering software could be used as
well.
[0031] Moreover the data contained in digital format which
represents wall thickness of each incremental section of a tubular
and the location of that section can be used in computations which
predict the actual effect on the tubular to various stressors,
including tensile, bending, collapse and burst forces, aging, etc.
Particularly useful by sequential inspection of a tubular, is the
ability to analyze changes which have occurred over a period of
time, and thereby be able to accurately predict, prior to failure
of the tubular, when failure is likely to occur, thereby avoid
same, but at the same time maximize use of the tubular.
[0032] In addition to the discussion above, the data can be
associated with other measurements of the tubular which may be of
interest. For instance other means, such as cam following means,
ultrasonic means, laser means, and other means for collecting
pertaining to ovality of the tubular can also be associated with
wall thickness data, positional information or both. Likewise, not
only may wall thickness and ovality data be associated with
positional information, but data derived from other means
(typically ultrasonic means generating "sheer waves") designed to
detect defects within the wall of the tubular, such as inclusions,
voids, delaminations, etc. may also be associated with positional
data. By so doing this other information would thereby become
subject to display, presentation, analysis or other use as
three-dimensional data.
[0033] It is thus to be appreciated that a process established in
accordance with the principles and teachings of the present
inventive disclosure constitutes an advancement in the field of art
to which the invention pertains. While the above description
contains many specificities, these should not be construed as
limitations on the scope of the invention, but rather as an
exemplification of preferred embodiments thereof. Accordingly, the
scope of the present invention should be determined not by the
embodiments illustrated, but by such claims as may be allowed and
their legal equivalents.
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